This invention relates to an earth boring machine. More specifically, this invention relates to a hydraulic earth boring machine operable to form generally horizontal passageways for conduits, cables, etc. beneath an established surface such as a roadway or the like without disturbing the roadway surface.
Underground conduits and the like are frequently placed by digging a trench to a desired depth laying, a continuous or articulated conduit within the trench, and then backfilling the trench. In some situations, however, it may be undesirable to utilize conventional pipe laying techniques. In this connection, it can be highly disruptive to traffic patterns to trench across an established roadway. Moreover, after conduit installation is completed, it is necessary to rebuild the roadway surface. This repaired strip is frequently subject to settling and/or wear damage that can create a potential traffic hazard. Further, in areas of high intensity piping, such as a chemical processing plant or the like, short run elevations in ground surfaces make piping installation by conventional trenching techniques difficult and burdensome.
In the above and other instances, it would be highly desirable to be able to form generally horizontal passageways beneath an established surface without forming a convention vertical trench.
In this connection, a number of machines have been at least theorized to provide generally horizontal earth passages for relatively short distances. Previously known horizontal boring of trenching machines are first mounted within an excavated area or trench adjacent a roadway or the like. A relatively small rod is then driven by the machine to pierce beneath the roadway to an excavated area on the opposite side. An enlarged head is then fitted onto the piercing rod and the rod is drawn back through the bore to increase the passageway to a size suitable to receive an underground conduit.
Earth boring machines which have been previously known have tended to be either hand operated, thus lacking in power, or relatively heavy hydraulic units, which are difficult to transport to a site and burdensome to manipulate and align in situ. In a similar manner many previously known units have tended to be somewhat large, intricate in design and difficult to handle and manipulate in confined quarters. Still further, many previously known machines have been somewhat unstable in operation and permit unacceptable bore hole deviation.
Additionally, some have devised rotary and/or water injection systems. These devices have proven to be relatively complex and in some instances have been deemed unacceptable for use by local ordinances and/or regulations.
The difficulties suggested in the preceeding are not intended to be exhaustive, but rather are among many which may tend to reduce the effectiveness and operator satisfaction with prior earth boring equipment. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that earth boring machines appearing in the past will admit to worthwhile improvement.